<?php
/**
 * CAssetManager class file.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @link http://www.yiiframework.com/
 * @copyright Copyright &copy; 2008-2011 Yii Software LLC
 * @license http://www.yiiframework.com/license/
 */


/**
 * CAssetManager is a Web application component that manages private files (called assets) and makes them accessible by Web clients.
 *
 * It achieves this goal by copying assets to a Web-accessible directory
 * and returns the corresponding URL for accessing them.
 *
 * To publish an asset, simply call {@link publish()}.
 *
 * The Web-accessible directory holding the published files is specified
 * by {@link setBasePath basePath}, which defaults to the "assets" directory
 * under the directory containing the application entry script file.
 * The property {@link setBaseUrl baseUrl} refers to the URL for accessing
 * the {@link setBasePath basePath}.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @version $Id: CAssetManager.php 3289 2011-06-18 21:20:13Z qiang.xue $
 * @package system.web
 * @since 1.0
 */
class CAssetManager extends CApplicationComponent
{
    /**
     * Default web accessible base path for storing private files
     */
    const DEFAULT_BASEPATH='assets';
    /**
     * @var boolean whether to use symbolic link to publish asset files. Defaults to false, meaning
     * asset files are copied to public folders. Using symbolic links has the benefit that the published
     * assets will always be consistent with the source assets. This is especially useful during development.
     *
     * However, there are special requirements for hosting environments in order to use symbolic links.
     * In particular, symbolic links are supported only on Linux/Unix, and Windows Vista/2008 or greater.
     * The latter requires PHP 5.3 or greater.
     *
     * Moreover, some Web servers need to be properly configured so that the linked assets are accessible
     * to Web users. For example, for Apache Web server, the following configuration directive should be added
     * for the Web folder:
     * <pre>
     * Options FollowSymLinks
     * </pre>
     *
     * @since 1.1.5
     */
    public $linkAssets=false;
    /**
     * @var array list of directories and files which should be excluded from the publishing process.
     * Defaults to exclude '.svn' files only. This option has no effect if {@link linkAssets} is enabled.
     * @since 1.1.6
     **/
    public $excludeFiles=array('.svn');
    /**
     * @var integer the permission to be set for newly generated asset files.
     * This value will be used by PHP chmod function.
     * Defaults to 0666, meaning the file is read-writable by all users.
     * @since 1.1.8
     */
    public $newFileMode=0666;
    /**
     * @var integer the permission to be set for newly generated asset directories.
     * This value will be used by PHP chmod function.
     * Defaults to 0777, meaning the directory can be read, written and executed by all users.
     * @since 1.1.8
     */
    public $newDirMode=0777;
    /**
     * @var string base web accessible path for storing private files
     */
    private $_basePath;
    /**
     * @var string base URL for accessing the publishing directory.
     */
    private $_baseUrl;
    /**
     * @var array published assets
     */
    private $_published=array();

    /**
     * @return string the root directory storing the published asset files. Defaults to 'WebRoot/assets'.
     */
    public function getBasePath()
    {
        if($this->_basePath===null)
        {
            $request=Yii::app()->getRequest();
            $this->setBasePath(dirname($request->getScriptFile()).DIRECTORY_SEPARATOR.self::DEFAULT_BASEPATH);
        }
        return $this->_basePath;
    }

    /**
     * Sets the root directory storing published asset files.
     * @param string $value the root directory storing published asset files
     * @throws CException if the base path is invalid
     */
    public function setBasePath($value)
    {
        if(($basePath=realpath($value))!==false && is_dir($basePath) && is_writable($basePath))
        $this->_basePath=$basePath;
        else
        throw new CException(Yii::t('yii','CAssetManager.basePath "{path}" is invalid. Please make sure the directory exists and is writable by the Web server process.',
        array('{path}'=>$value)));
    }

    /**
     * @return string the base url that the published asset files can be accessed.
     * Note, the ending slashes are stripped off. Defaults to '/AppBaseUrl/assets'.
     */
    public function getBaseUrl()
    {
        if($this->_baseUrl===null)
        {
            $request=Yii::app()->getRequest();
            $this->setBaseUrl($request->getBaseUrl().'/'.self::DEFAULT_BASEPATH);
        }
        return $this->_baseUrl;
    }

    /**
     * @param string $value the base url that the published asset files can be accessed
     */
    public function setBaseUrl($value)
    {
        $this->_baseUrl=rtrim($value,'/');
    }

    /**
     * Publishes a file or a directory.
     * This method will copy the specified asset to a web accessible directory
     * and return the URL for accessing the published asset.
     * <ul>
     * <li>If the asset is a file, its file modification time will be checked
     * to avoid unnecessary file copying;</li>
     * <li>If the asset is a directory, all files and subdirectories under it will
     * be published recursively. Note, in this case the method only checks the
     * existence of the target directory to avoid repetitive copying.</li>
     * </ul>
     * @param string $path the asset (file or directory) to be published
     * @param boolean $hashByName whether the published directory should be named as the hashed basename.
     * If false, the name will be the hashed dirname of the path being published.
     * Defaults to false. Set true if the path being published is shared among
     * different extensions.
     * @param integer $level level of recursive copying when the asset is a directory.
     * Level -1 means publishing all subdirectories and files;
     * Level 0 means publishing only the files DIRECTLY under the directory;
     * level N means copying those directories that are within N levels.
     * @param boolean $forceCopy whether we should copy the asset file or directory even if it is already published before.
     * This parameter is set true mainly during development stage when the original
     * assets are being constantly changed. The consequence is that the performance
     * is degraded, which is not a concern during development, however.
     * This parameter has been available since version 1.1.2.
     * @return string an absolute URL to the published asset
     * @throws CException if the asset to be published does not exist.
     */
    public function publish($path,$hashByName=false,$level=-1,$forceCopy=false)
    {
        if(isset($this->_published[$path]))
        return $this->_published[$path];
        else if(($src=realpath($path))!==false)
        {
            if(is_file($src))
            {
                $dir=$this->hash($hashByName ? basename($src) : dirname($src));
                $fileName=basename($src);
                $dstDir=$this->getBasePath().DIRECTORY_SEPARATOR.$dir;
                $dstFile=$dstDir.DIRECTORY_SEPARATOR.$fileName;

                if($this->linkAssets)
                {
                    if(!is_file($dstFile))
                    {
                        if(!is_dir($dstDir))
                        {
                            mkdir($dstDir);
                            @chmod($dstDir, $this->newDirMode);
                        }
                        symlink($src,$dstFile);
                    }
                }
                else if(@filemtime($dstFile)<@filemtime($src) || $forceCopy)
                {
                    if(!is_dir($dstDir))
                    {
                        mkdir($dstDir);
                        @chmod($dstDir, $this->newDirMode);
                    }
                    copy($src,$dstFile);
                    @chmod($dstFile, $this->newFileMode);
                }

                return $this->_published[$path]=$this->getBaseUrl()."/$dir/$fileName";
            }
            else if(is_dir($src))
            {
                $dir=$this->hash($hashByName ? basename($src) : $src);
                $dstDir=$this->getBasePath().DIRECTORY_SEPARATOR.$dir;

                if($this->linkAssets)
                {
                    if(!is_dir($dstDir))
                    symlink($src,$dstDir);
                }
                else if(!is_dir($dstDir) || $forceCopy)
                {
                    CFileHelper::copyDirectory($src,$dstDir,array(
						'exclude'=>$this->excludeFiles,
						'level'=>$level,
						'newDirMode'=>$this->newDirMode,
						'newFileMode'=>$this->newFileMode,
                    ));
                }

                return $this->_published[$path]=$this->getBaseUrl().'/'.$dir;
            }
        }
        throw new CException(Yii::t('yii','The asset "{asset}" to be published does not exist.',
        array('{asset}'=>$path)));
    }

    /**
     * Returns the published path of a file path.
     * This method does not perform any publishing. It merely tells you
     * if the file or directory is published, where it will go.
     * @param string $path directory or file path being published
     * @param boolean $hashByName whether the published directory should be named as the hashed basename.
     * If false, the name will be the hashed dirname of the path being published.
     * Defaults to false. Set true if the path being published is shared among
     * different extensions.
     * @return string the published file path. False if the file or directory does not exist
     */
    public function getPublishedPath($path,$hashByName=false)
    {
        if(($path=realpath($path))!==false)
        {
            $base=$this->getBasePath().DIRECTORY_SEPARATOR;
            if(is_file($path))
            return $base . $this->hash($hashByName ? basename($path) : dirname($path)) . DIRECTORY_SEPARATOR . basename($path);
            else
            return $base . $this->hash($hashByName ? basename($path) : $path);
        }
        else
        return false;
    }

    /**
     * Returns the URL of a published file path.
     * This method does not perform any publishing. It merely tells you
     * if the file path is published, what the URL will be to access it.
     * @param string $path directory or file path being published
     * @param boolean $hashByName whether the published directory should be named as the hashed basename.
     * If false, the name will be the hashed dirname of the path being published.
     * Defaults to false. Set true if the path being published is shared among
     * different extensions.
     * @return string the published URL for the file or directory. False if the file or directory does not exist.
     */
    public function getPublishedUrl($path,$hashByName=false)
    {
        if(isset($this->_published[$path]))
        return $this->_published[$path];
        if(($path=realpath($path))!==false)
        {
            if(is_file($path))
            return $this->getBaseUrl().'/'.$this->hash($hashByName ? basename($path) : dirname($path)).'/'.basename($path);
            else
            return $this->getBaseUrl().'/'.$this->hash($hashByName ? basename($path) : $path);
        }
        else
        return false;
    }

    /**
     * Generate a CRC32 hash for the directory path. Collisions are higher
     * than MD5 but generates a much smaller hash string.
     * @param string $path string to be hashed.
     * @return string hashed string.
     */
    protected function hash($path)
    {
        return sprintf('%x',crc32($path.Yii::getVersion()));
    }
}
